Thursday, September 11, 2014

Humans Could Be In The Middle Of A Huge Evolutionary Transition//Christina Sterbenz

Mankind is undergoing a major evolutionary transition comparable to the shifts from prosimians to monkeys, monkeys to apes, and apes to humans, according to Cadell Last, an evolutionary anthropology Ph.D. student and researcher at the Global Brain Institute.

Human life expectancy has already increased from about 45 at the start of the 20th century to 80 today. Last predicts it will increase to 120 as soon as 2050 — a concept known as radical life extension — through a combination of new technology, behavior, and natural selection.

In addition to longer lives, humans will demonstrate delayed sexual maturation and biological reproduction, according to Last. Taken together, these changes could signify a new type of human.

From "Living Fast And Dying Young" To "Living Slow And "Dying Old"

According to life history theory, natural selection shapes the length of an organism's life and the timing of key events to produce the most surviving offspring. In the "fundamental life history trade-off," organisms must choose between spending their time producing as many offspring as possible or rearing those offspring to make them as successful as possible, according to Last.

And as brain sizes increases, organisms require more energy and longer rearing time to reach their full potentials.

Based on these ideas, three major shifts in primate history have occurred toward longer lives and delayed reproduction: between prosimians and monkeys, monkeys and apes, and apes and humans.

Humans already dedicate the most time and energy toward nurturing offspring of any primate species, and this pattern is only becoming more extreme.

"Human life history throughout our species evolution can be thought of as one long trend towards delayed sexual maturation and biological reproduction (i.e. from 'living fast and dying young' to 'living slow and dying old')," Last writes.

While physical needs fueled previous evolutionary changes, cultural and technological innovations will drive the next shift, which has been accelerating since the Industrial Revolution.

Simply said, humans need more time to develop to take advantage of our complex world.

Biological Vs. Cultural Reproduction

Considering recent advancements like in-vitro fertilization, egg-freezing, and even adoption, the mechanics of biological reproduction have radically changed. "The biological clock isn't going to be around forever," Last says — or at least, people can turn it off or ignore it for a while.

Today, and even more so in the future, the success of individual and collective human life depends on knowledge and economic prosperity. Passing on new and important ideas to the next generation involves a process called cultural reproduction, which takes more time and energy than simply having babies.

"You have a limited amount of time and energy from birth to death, and you've got to figure out whether you're going to dedicate that time and energy toward biological reproduction or cultural reproduction," Last explains. "We're opting to take ourselves out of the gene pool in favor of immersing ourselves in an idea pool."

Even now, we've seen evidence of delayed reproduction and fewer offspring per person in many countries. Despite fears of overpopulation, Last points out that more than half of countries (with available data) have reached a replacement fertility rate of less than 2.1, as shown in his chart below, compiled from the CIA's World Factbook.

"As countries become socioeconomically advanced, more and more people, especially women, have the option to engage in cultural reproduction," Last explains.

What's more, the emergence of artificial intelligence will offset the need for low-skill, low-education jobs, giving individuals the "opportunity to explore cultural reproduction as a vocation," Last writes. In many cases, biological reproduction has even become "too costly" in the face of the increasing pressure to adapt to technological advancements.

Altogether, the world should expect a variety of humans who live much longer and have kids much later than what Last calls archaic humans.

"These are sort of the beginning signs that we're making a transition to a radical life extension — within 20 or 30 years," Last says.

Meanwhile, technology has changed human interaction in many ways. Already, a reporter in New York can talk to an evolutionary anthropologist in Canada over Skype. In another few decades, nanotechnology could allow similar conversations to occur entirely in the brain.

"Your 80 or 100 is going to be so radically different than your grandparents," Last says.